Pressure system



April 12, 1932. H. s. PAR'DEE 1,853,925

' PRESSURE SYSTEM 7 Filed Feb. 9, 1951 Pr 1 w 0, [3 52. 5

11 AC 'AC" BR L7 DV w M f7 showin an alternative arrangement PatentedApr. 12, 19,32

hUNITED STATES PATENT OFFICE.

HARV'EY S. PARIDECE, OF RAVINIA, ILLINOIS, ASSIGNOR T JOHN ROBERTBLAGKHALL,

OF HIGHWOOD, ILLINOIS PRESSURE SYSTEM Application filed February 9,1931. Serial No. 514,442.

, This invention relates to fluid pressure systems, and with regard tocertain more specific features, to fluid pressure systems utilizing amixture of gaseous and liquid fluids.

AJnong the several objects of the invention may be noted the provisionof apparatus in a liquid fluid pressure line for separating foreigngaseousfluids therefrom; the provision of apparatus of the classdescribed located in a liquid pressure line adapted to provide an overall uni-directional flow of gas therein; the provision of apparatus ofthe class described comprising at least one trap in a liquid pressureline adapted to perform said separation; and the provision of apparatusof the class described adapted to prevent intermixing of saturated andunsaturated fluids contained. in said line. Other objects will be inpart obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structurehereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated two of variouspossible'embodiments of the invention,

Fig. 1 is a diagrammatic, hydraulic circuit showing one arrangement ofthe invention and,

Fig. 2 is a diagrammatic, .hydraulic circuit of the invention.

Similar reference characters indicate cor-- responding parts throughoutthe severa views of the drawings. 7

In operating expansive work chambers or the like by means of a liquidpressure, using compressed gas as an energy storage medium, the liquidused normally contains a certain amount of the gas in solution. Theamount of gas in solution varies among other things, with the pressure.Thus when the liquid is under a comparatively high pressure, a certainamount of gas is dissolved in the liquid, a part of which will come outof solutionwhen the pressure is relieved, as when the work chamber orthe like is exhausted. When the gas comes out of solution .under suchconditions of decreased pressure, bubbles of gas form in the liquid andrise and accumulate in the work chamber. This gas remains in the chamberor in other pockets in the system and must be compressed each time thatliquid pressure is transmitted. This results in not only unnecessarilyincreasing the amount of liquid which must be used in each operation,

but also in introducing a larger degree of 1 time lag in operation. Inshort, a hydraulic system using a compressible gas as an energy storagemedium is thus rendered slow and wasteful in operation.

The present invention as illustrated in Figs. 1 and 2, may be adaptedfor use, for example, in connection with the fluid pressure systems setforth in my United States Patent 1,784,310, issued December 9,1920 andreissued as No. 18,033 of April 7 1931.

Referring now more particularly to Fig. 1, the diagrammatic, hydrauliccircuit shown includes an expansive chamber, or working cylinder BRconnected, through a three-way valve BV, to a pressure tank PT and asump tank ST. The working cylinder BB is provided with a piston,comprising an internal, compressible bellows 11, which is positivelyleak-proof and which is exposed to fluid pressure from the tank PT. Thebellows 11 is connected to a linkage 5, which operates a brake 9,adapted to press against a vehicle or like wheel 7. The movement of thelinkage 5, as shown in Figs. 1 and 2, is suflicient to operate the brake9. It will be understood that other apparatus may be operated by thepressure system and that the working cylinder BR may be replaced by anyothersuitable engine or other means for obtaining work from a liquidunder pressure, the braking arrangement being shown by way of exampleonly.

The brake valve BV comprises a three-way, valve of the tapered plug, orother suitable type. It is adapted to connect either the tank 113% orthe tank ST with the working cylinder The tank PT comprises a pressuretank designed to withstand the pressure used, and to .be air, oil, andwater tight. For example, the

tank pressure may be constructed to hold safely a pressure of onehundred pounds per square inch. The sump tank ST is usually underatmospheric pressure, and is positioned to receive the drainage from theworking cylinder BR.

Interposed in series between the valve BV and the working cylinder BR,are traps AC comprising upright cylindrical tanks as shown in Fig. 1, orother suitable regions of increased capacity in the connecting lines.The top of the first trap AC is connected to the valve BV and then tothe tanks PT and ST by line 23 and lines 19 and 17 respectively. Thebottom of the trap AC is connected to the expansive chamber or workingcylinder BR by a line 26.

Each trap AC preferably has a capacity larger than the displacement ofthe engines BR. The traps AC may be formed as a plurality of smallertraps in which case the sum of the capacities of the plurality of trapsis preferably larger than the displacement of the engines BR. I

It is to be understood that apparatus not shown in the drawings, butdescribed in detail in mysaid United States Patent 1,784,310 (reissuedas No. 18,033 of April 7, 1931) is adapted to transfer fluid from tankST into the pressure tank PT, as shown diagrammatically in Fig. 2.

The operation of the invention as shown in Fig. 1 is as follows:

The lines 24 and 26, joining the trap AC, the working cylinder BR, andthe valve BV, as well as the cylinder and the traps themselves arefilled with an unsaturated liquid. This hydraulic liquid preferablycomprises a liquid relatively non-expansive and non-compressible ascompared with gases." The same fluid is supplied to the pressure tankPT, but in the tank it is subjected to pressure with entrapped gas someof which incidentally dissolves in the liquid, under said pressure. Thetank ST is under atmospheric pressure, hence the liquid containedtherein does not contain an appreciable amount of dissolved gas ascompared to the saturated liquid in the .pressure tank. It is relativelyunsaturatd V The requirement that the capacity of the chambers or trapsAC be preferably somewhat greater than the displacement of the workcylinder BR (or cylinders, as the case may be) is desirable because theentering saturated'liquid should never completely fill the traps AC aswould be the case if the displacement of the working cylinder BB weregreater than that of the traps. I

On the working stroke the first chamber or trap AC is partly filled atthe top with saturated liquid from the tank PT which.

forces ahead of it the unsaturated liquid out of the bottom of the firsttrap AC through line'24 intothe next trap AC then through rated liquid,which entered the first trap AC is released and this released air rises.

to the top of the trap and is pushed through lines 23 and 17 into thesump tank ST by the action of the return stroke of the work cylinder.

One such trap AG in the line is efficient but greater security isafforded if several traps AC and AC are locatedin the line at suchintervals that the capacity of the pipe such. as 24 connecting them isless than the displacement of the working chambers. Thus if at the startof the operation of the traps AC, the connecting lines 24 and 26 and theWorking chamber BR are filled with unsaturated liquid it is practicallyimpossible for any gas entering with the saturated liquid to passforward as far as the working cylinder BR. Each succeeding trap has onlyto take care of a possible increment of the expelled dissolved gaspassed up by the trap immediately ahead.

Referring now more particularly to Fig. 2 which shows a modification ofthe arrangement of the traps AG in the system, the indicia PT, ST and ERrepresentrespectively the pressure tank, sump tank and working cylinderwhich are identical to those shown in Fig. 1. The sump tank ST containsrelatively unsaturated liquid and is under atmospheric-pressure whereasthe pressure tank contains liquid under a higher pressure. The engine BRor engines, as the case may beyare connected with the valve BV by line23. Other connections to the valve BV will be pointed out hereinafter.

There is shown at PU a hydraulic pump for transferring unsaturatedliquid from the tank ST to the tank PT. The pump PU is driven by themotor M which may also be the prime mover for a vehicle, to which thissystem is applied. The pump PU is connected with tanks ST and PT bymeans of lines 25, 19, 20 and 18, respectively. A check valve CV isinserted in the line 19 to controllably prevent flow of liquid from thetank PT to the pump when the pump is not working.

The traps AC instead of being positioned between thevalve BV and theengines BR are in this embodiment positioned between the tanks PT andvalve BV. The bottom of the first trap AC is connected with the prmipPUby line 19. The top of the trap AC is connected with the bottom of thesecond trap AC by line 20, and the top of trap AC is connected with thebottom of the pressure tank PT by line 18; Thus the liquid or fluid fromthe pump PU enters the bottom pumped directly' of AC goes to the bottomof AC and thence to the pressure tank PT.

The traps AC have a considerable capacity, preferably larger than thesum total of the displacements of the working cylinders orengines BRwhich may be in the system.

The valve BV as shown in Fig. 2, is connected to the tank PT by thelines 16 and 19, the trap AC the line 20, the trap AC and the line 18.Line 17 connects the valve BV with the tank ST. The line 16 taps theline 19 between the valve CV and the trap The operation of thisalternative system is as follows:

With thevalve BV closed, as is shown in Fig. 2, and the pump PU beingoperated bythe motor M, unsaturated liquid from the The liquid in thetank PT becomes saturated with the gas, with which it is in contact inthe tank PT. It 'is to be noted that the liq-- uid which finally fillsthe trap AC although under pressure, is not saturated with gas,inasmuchas it does not come in contact with such gas while underpressure.

When the working chamber BB is connected with boththe pump PU and thepressure tank PT and the traps AG by way of the lines 23, valve BV,lines 16 and 19, unsaturatedliquid from pump PU and/or from the bottomof the first trap AC? .is forced into lines 16 and 23 to the workingcylinder BR,

' thereby causing the bellows 11 to compress.

Thus it is seen that although the liquid in the tank PT may be saturatedwith gas, only unsaturated liquid reachesthe cylinder BR,

since the" lines 19 and 16 at the valve BV, contain only relativelyunsaturated liquid, from the'tank ST into the first trap AC 1 If thevalve BV- is now operated-to cut off the connectionbetween the lines 16and 23, and to open the connection between the lines23 and 17, therebyconnecting the'cylinder BR with the sumptank ST, the bellows '11expands, forcing a proportional amount pf unsaturated liquid from thelines 23 and 17 into the tank ,ST, sutficient unsaturated liquidremaining in the working cylinder BR andthe line 23, nevertheless, tocompletely fill the volume enclosed therein.

While the pump PU is operating, unsaturated liquid may be used directlyfrom the pump, up to the limit of its capacity, to supply the workingcylinders BR. At other times, when the pump PU is stopped, the

first trap AC which also contains unsaturated liquid, supplies thecylinders BR.

Since saturated liquid is not used in the cylinder BR there results butlittle or no diminution of the entrained air in the pressure tank.Moreover, if the pump PU pumps both gas and liquid, the gas entering thefirst trap AC immediately rises to the top, and is forced along tothenext trap AC in which it rises to the top and discharges into theressure tank PT.

All a vantage of this modification is the assurance that even thoughliquid is withdrawn by the l1ne=23faster than it ispumped by the pumpPU, air in the traps AG will remain at the top. The arrangement makesthe flow of air uni-directional, in the direction of the tank isbi-directional: Another advantage of the arrangement of the traps AC asshown in PT, while the flow of liquid Fig. 2 is that a pump may be usedwhich is ada -ted to pump certain quantities of gas as wel as of liquid.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in car rying out the above constructionswithout departing from the scope of the invention,

.it is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeand not in a limiting sense.

I claim:

1. In combination in a closed gas and liq-' uid pressure system, apressure tank, a pump supplying said pressure tank and joined to saidpressure tank by means of a connecting line, and at least two chambersinterposed in series in said line,,each having a large capacityinrelation to the connecting lines in said system, one of said chambersbeing adapted to receive fluid fromsaid pump at the bottom thereof anddeliver said fluid from the top'thereof to the bottom of said secondchamber, said second chamberbeing adapted to deliver said fluid from thetop thereof to the pressure tank.

2. In combination in a closed gas and liquid pressure system, a pressuretank, a pump supplying said pressure tank and joined to said pressuretank by means ofa connecting line, and at least two chambers interposedin series in said line, each having a large capacity in relation to theconnecting lines in said system, one ofsaid chambers being adapted toreceive fluid at the bottom thereof, from said pump and deliver saidfluid from the top thereof to the bottom ofsaid second chamber,

said second chamber being adapted to de- 3. In combination with a gasand liquid pressure system having gas-saturated and unsaturated liquid,an engine and a pressure tank, saidengine being connected with saidpressure tank by a connecting line, said -pres sure tank havingsaturated liquid therein, said engine and at least part of saidconnecting line having unsaturated liquid therein, and at least onechamber interposed in said connecting line, the bottom of said chamherbeing connected with said engine, and the top of said chamber beingconnected with said pressure tank.

4. In combination with a gas and liquid pressure system havinggas-saturated and unsaturatedliquid, an engine and a pressure tank, saidengine being connected with said pres sure tank by a connectingline,-said pressure tank having saturated liquid therein, said en gineand at least part of said connecting line having unsaturated liquidtherein, and at least two chambers interposed in series in saidconnecting ]ine,-said engine being connected to the bottom of one ofsaid chambers, the top thereof being connected with the bottom of theother of said chambers, the top of said other chamber being connectedwith said pressure tank, whereby gas escaping from said saturated liquidis prevented from reaching said engine.

In testimony whereof I have signed my name to this specification thissixth day of February, 1931.

HARVEY S. PARDEE.

